Crash attenuation devices have been developed for mounting on vehicles that are parked or moving slowly on roadways, for example at construction or maintenance sites, in order to attenuate the impacts from collisions with the parked vehicle. Often times, vehicles equipped with crash attenuators are purposely deployed around work sites to shield workers at the site from being hit. Instead, errant vehicles strike the attenuator which arrests the motion of the errant vehicle and dissipating its impacting energy. Examples of these attenuation devices are disclosed in U.S. Pat. Nos. 6,186,565, 6,098,767, 5,052,732, 4,635,981, and 4,658,941.